Remote radio receiver tuning indicating apparatus



J. G. BLACK Nov. 18, 1952 REMOTE RADIO RECEIVER TUNING INDICATING APPARATUS Original Filed Oct. 29, 1945 3 Sheets-$heet l JNVENTOR James 6. Black Nov. 18, 1952 J BLAK 2,618,694

REMOTE RADIO RECEIVER TUNING INDICATING APPARATUS Original Filed Oct. 29, 1945 3 Sheets$heet I5 FIG. 5

w 5 N x N 5 OJ 03 (\J lnvenfor James 6 Black By Want/ Wu xQ/W Affys.

Patented Nov. 18, 195 2 REMOTE RADIO RECEIVER TUNING INDICATING APPARATUS James G. Black, Chicago, 111., assignor to A. C. Nielsen Company, Chicago, 111., a corporation of Illinois Original application October 29, 1945, Serial No. 625,371. Divided and this application August 19, 1948, Serial No. 45,188

2 Claims. 1

The present invention relates to remote radio receiver tuning indicating apparatus and is a division of copending application, Serial No. 625,371, filed October 29, 1945, which has for its primary object the provision of new and improved apparatus of the aforementioned character.

Another object of the present invention is the provision of new and improved apparatus for indicating at a remote point, which may be a central indicating or recording station, the tuning of a radio receiver located at a point distant from v the recording station, as in the home of the owner of the receiver.

A further object of the present invention is to provide new and improved radio receiver tuning indicating apparatus including means for accurately indicating the tuning of a radio receiver, which means is operatively connected to the radio receiver through a suitable line, such as a telephone line.

A further object of the present invention is the provision of a new and improved remote radio receiver tuning indicating apparatus comprising a balanced circuit including a telephone line or the like and variable impedance means associated with the radio receiver whose tuning is to be indicated and which unbalances the circuit when the tuning is changed and other variable impedance means located at a central station which is operated to rebalance the circuit.

A further object of thepresent invention is to provide a new and improved apparatus of the character set forth in the preceding paragraph including motor operated variable resistors associated both with the radio receiver and with the central station apparatus.

A further object of the present invention is to provide a new and'improved tuning indicating apparatus including a balanced circuit and means for substantially unbalancing the circuit when the tuning is varied thereby to eiiect operation of the indicating means over a considerable range each time thetuning is changed to provide greater accuracy.

A further object of the present invention i to provide a new and improved radio receiver tuning indicatingapparatus including an indicator member moved to different positions by a motor and means for dynamically stopping the motor, thereby to insure greater accuracy of indications.

Another object of thepresent invention'is the provision of a new and improved means for dynamically stopping a motor, and more specifi- 2 cally, a means including a normally charged capacitor dischargeable through a motor winding for quickly and effectively stopping the motor.

A further object of the present invention is to provide radio receiver tuning indicating apparatusincluding new and improved means for indicating when the receiver is turned oh and also when the indicating means is disconnected from the receiver, as by an open circuit in the telephone line, and further, including means for signalling the two above mentioned conditions.

Another object of the present invention is the provision of new and improved radio receiver tuning indicating apparatus including means for indicating the station to which the receiver is tuned and alsothe network to which the station is connected.

A further object is the provision of new and improved readily changed visual indicating means especially suited for indicating the network to which a radio receiver is tuned.

Other objects and advantages of the present invention will become apparent from the ensuing description of an embodiment of the invention in which reference is had to the accompanying drawing, in which:

Fig. 1 is a schematicrepresentation of one embodiment of the invention;

Fig. 2.is a side elevational view of a visual indicator control mechanism utilized in the invention andwhich is only diagrammatically illustrated in Fig. 1;

Fig. 3 is a fragmentary plan view of the mechanism;

Fig. 4 is a fragmentary vertical cross-sectional view taken generally along the line 4-4 of Fig. 2; and

Fig. 5 is an enlarged cross-sectional view taken along the line 5-5 of Fig. 4.

In brief, the present invention has for its primary purpose the indication or recording, or both, at acentralstation the various broadcast stations to which a radio receiver located in the home of the radio owner is tuned. It comprises a balanced circuit extending between the home and station, which circuit preferably includes a telephone line between the two locations. The balance of the circuit is changed when the tuning. of a radio receiveris changed and the unbalance results in the operation of'indicating or recording means at the station to a point corresponding to the newly selected station by means which restores the balance of the circuit.

The apparatus of the present invention comprises, in the main, two units, the first of which is indicated by reference character It) and is located at the central point or station and a second unit, indicated by the reference character :2, which is coupled to a radio receiver. The two units are coupled to each other preferably through a telephone circuit including the conductors i4 and IS. The units may be permanently coupled or may be coupled at desired or selected times through a telephone exchange, not shown.

While the figure illustrates apparatus for indicating or recording the tuning of a single receiver, it should be understood that the tunin of any number of receivers may be recorded by similar apparatus for each of the receivers whose operation is to be indicated or recorded.

The coupling between the units I and i2 is effected primarily through a balanced circuit including the telephone lines [4 and [6. The balanced circuit is preferably of the bridge type and preferably includes continuously variable impedance means, such as resistors 2c and 22, associated with the radio receiver and indicating or recording apparatus, respectively. The value of resistor 20 is controlled in response to the tuning of the radio receiver and changes in tuning effects changes in the value of the resistor to unbalance the circuit. The circuit balance is restored by adjustment of resistor 22, the value of which and the position of the adjusting means of which are thus indicative of the radio station to which the receiver is tuned. The resistors may be of the rotary type and have resistances of about 10,000 ohms. Resistor 22 also has an open circuit position for a purpose which will appear hereafter.

The bridge circuit includes in addition to the telephone line and resistors 20 and 22, a pair of fixed resistors 2d and 26 and an adjustable line balancer resistor 28 connected in series with resistor 22. Resistors 22-28. 24 and 26 constitute three legs of the bridge and the fourth leg includes the resistor 20 associated with the radio receiver. Resistors 24, 26, and 28 may also have values of about 10,000 ohms.

The bridge circuit is energized with direct current supplied to it through a pair of conductors 32! connected to a suitable source of direct current, which source may include a dry disc type rectifier 52 and a filter 34. The rectifier is connected to the secondary winding 36 of a transformer 38, the primary Winding lfl of which is connected to a pair of conductors d2 leading to a suitable source of alternating current, as through a power switch 64 and a plug type connector Q6.

The bridge circuit has its output terminals 50 and 52 connected to indicating and recording means and to power means controlling the variable resistor 22 in a manner to be described in greater detail shortly through conductors and 50.

The value of the variable resistor 20 associated with the receiver is varied in response to the tuning of the receiver and unbalances the bridge circuit when the tuning is changed. It is preferred that its value be varied by a slow speed (such as 1. R. P. M.) unidirectional motor Bil mechanically connected to a movable resistor contact 62. The motor may comprise a part of an electronic device coupled to a radio receiver and operable to positions indicative of the tuning of the radio receiver and thus to the various broadcast stations to which the receiver is tuned. This electronic device may be of the type disclosed and claimed in the copending application of Robert A. Clark, Jr., application Serial No. 511,246, filed November 22, 1943, now Patent 2,483,573, assigned to the assignee of this application. The electronic device is not illustrated nor will it be described in detail. It is believed suificient to say that it includes a relay 6 1 which is adapted to be energized whenever the radio receiver is turned on. This relay is utilized to operate a movable switch blade 65 to connect the resistor 20 to the bridge circuit when the relay is operated. When operated, switch blade 66 interconnects telephone line 14 and a conductor 68 leading to the movable contact 52 associated with resistor 20.

The electronic device also includes the previously referred to motor 60 mechanically connected to a variable capacitor 70 forming part of the electronic control. The motor is so controlled that it is energized, when the tuning of the receiver is changed, to operate the capacitor Hi to a point corresponding to the station to which the receiver is tuned. When this point is reached, the motor is deenergized and stopped. It will thus be apparent that the Value of resistor 20 is indicative of the station to which the receiver is tuned. The motor 60 is supplied with power through a pair of conductors 12 under the control of the electronic control device.

The unit [2 of the present invention associated with the receiver also includes means for unbalancing the bridge to a predetermined and unique extent to provide an indication of the operativeness of the radio receiver, thereby to provide an indication of the on and off periods of the receiver. This means includes an adjustable resistor i i, the value of which is preadjusted by means of a movable contact 76 and Which is substituted in the bridge circuit for resistor 20 when the radio receiver is turned off. The substitution is effected by the relay 6d, the switch blade 66 of which connects telephone line I l to the resistor through conductor 18 when the radio is turned oif and the relay Ed is deenergized. The relay 6!! may remain energized for a brief period after the receiver is turned off because of a delay in the cooling of a cathode of a rectifier tube, provided a tube using an indirectly heated cathode is used, as is used in the disclosure of said application. As a result the motor operates for a brief period when the receiver is turned ofi, and varying resistor 26, but this is not a disadvantage because of the substitution of the off resistor id when the relay is deenergized. Rather, the delay is an advantage because when the receiver is subsequently turned on the motor operates and changes capacitor 10 and resistor 20 to return these to values and positions corresponding to the station tuned before the set was turned off. The resistor Hi may have a value of about 10,000 ohms, of which about 6,000 ohms are used.

In order to increase the accuracy of the apparatus, means are provided for insuring that the indicating means is operated to a substantial extent each time the tuning of the receiver is varied. This means substantially unbalances the bridge circuit each time the tuning is varied. It includes a relay 80 connected in parallel with the motor 60 and therefore energized each time the motor is energized, i. e., each time the tuning of the receiver is varied, and a circuit unbalancing resistor 82 placed in the bridge circuit by the relay when it is energized. The resistor 82 is connected to telephone line l5 and to a conductor 84 leading to the common ends of the resistors '20 and 74. When the tuning is changed and the motor 60 energized, the resistor 82 is placed in circuit by operationofswitch blade :80 of relay 80,.whichremoves ashort circuit from .across the resistor. When the short circuit isthus removed,.the resistor :82 is placed in series withthe resistor 20 to unbalance the bridge circuit and to effect operation of the indicating means over a considerable range. The resistor 82 may have a value of about 30,000 ohms.

Theindicating or recording station unit J0 .includes means for indicating andpreferably .recording the station to whichtheradio receiver is tuned. This means includes a tape .type recorder '90 having a movable indicator-scribenQZ operated into diiferentpositions corresponding to the tuning of the radio receiver'by a unidirectional alternating current .motor -:.94 placed into operation when the circuit is unbalanced and whichris also mechanically.connectedto the movable contact-9.6 .of the variable resistora2-2 to correlate the position, of the scriber 92 .withthe position and value ofresistor22 and .thustothe tuning of the radioreceiver.

The tape type recorder 90 may be of various types and has therefore not been ,illustratedin detail. It may, however, include an electrical and spring type drive and speed reducing unit 08 for driving the tape I00 at a constant speed.

More specifically, the stylus arm 92 is mounted for universal movement at its end :SjZa and is adapted to be moved to bring its stylus 92?) thereof into engagement with the tape I-ilOin response'to energizationof a magnet 200. Movement of thestylus 92b transversely of the tape I00 to positions corresponding to stations to which the receiver I2 is tuned is eifected ,by crank connecting the stylus arm, 92 bymeans of a crank I941) to a crank wheelrl94a mounted for rotation with the drive shaft of the motor'9 4.

The motor-04 is placed into operation to move the scriber 92 and to adjust-resistor22 whenever the bridge circuit is unbalanced. Thiscontrol is-effected through a motor circuit controlling relay I02 including apair of switch'blades I04 nd d r a I08.; ab ithewlariz ed type and including a movable switch blade H0, and the energizationof which iscontrolled in response to the unbalance of the bridge. The relay I08 includes a winding II2 -which;is- ;energized whenever the bridge circuit is'unbalanced in either direction.

In order to increase the sensitivity-of the apparatus, the bridge circuit is coupled to the relay I08 through an amplifier indicated as a whole by reference character II4 andincluding apair of electron tubes H6 and H0. The tubes are preferably of the (SJ 6 type and-they are connected in diiferential relationship to the bridge circuit and to a relay winding II2 (having an impedance of about-6,000 ohms), which is connected across the anodes of the two-tubes through a resistor I20 (having a value of about 5,000 ohm s). Suitable anode potential is appliedto the anodes of the two tubes through resistors I20 and I22 (each of about 6j500 ohms), thecommon junction'of which is connected to ancdevoltage supplying conductor I24.

The anode potential is preferably supplied by v rectifying means of the electronic type including atube I 26 (as of the 80 typeyenergized through a transformer I28. The iiIarnentof-the tube is. supplied with -power--f rom a low voltage secondary winding- I30 of the-transformer. The directcurrent output of the-rectifier is: supplied to the conductorfI24 through ,afilter circuit I 32 and a voltage regulator tube I34, which may be of the VR-l50 type. The negative side of the direct current voltage is connected by conductor I36 to-the cathodes of theamplifiertubes [I6 and H8 through the cathode bias resistors I38 and I40, respectively (each of about 170 ohms).

The controlgrids of the tubes H6 and H8 are connected to the output terminals 50 and 52 of the bridge circuit through a normally closed test switch I42, the conductors 54 and 56 and resistors I44'and I46, respectively (each of about .1 megohm). The grid circuits are connected to the negative line I36 through resistors I48 and I50, respectively (each of about 5,000 ohms).

When the bridge circuit is balanced, no current flows through the winding I I2 of the polarized relay I08, a condition that is obtained through the use of adjusting means including a resistor I52 (of about 500 ohms) connected across resistors I38 and I40 and an adjustable contact I54 connecting the resistor I52 to the junction of resistors I38 and I40. The adjustment is made with the test switch I42 open, which brings about a condition corresponding to a balanced condition of the bridge when the terminals 50 and 52 are at the same potential.

When the bridge is unbalanced, current flows in one direction or the other through the winding I I2 with the result that the relay contact II 0 is moved from a normal circuit opening position to a circuit closing position to energize the winding of the relay I02. This energizing circuit extends from one of conductors 30 to the other through conductor I56, which may have a voltage reducing resistor I57 interposed therein, the relay winding, conductor I58, one or the other of the two contacts I 60 associated with the movable contact IIO, the movable .contact itself, and conductor I62.

When the winding of relay I02 is thus energized in response to the unbalance of the bridge circuit, the switch blades I04 and I06 are operated from a dynamic stopping position, which will be described in greater detail shortly, to a position to connect the motor 94 to a source of voltage, which source is preferably the volt supply. The energizing circuit for the motor extends through the pair of conductors I64, the switch blades I04 and I06, the pair of conductors I66, a normally closed manually operable motor switch I68 and the previously referred to conductors 42 leading to the plug type connector 46. When this circuit is closed, the motor 94 is energized and operates to adjust resistor 22 to restore the balance of the bridge circuit and to move the scriber 92 to a position corresponding to the position of contact 63 and the value of resistor 22.

When the bridge circuit has been balanced then, in accordance with one of the features of, my invention, the motor 94 is disconnected from its alternating current source power supply and quickly and effectively dynamically stopped bysupplying it with a pulse of current and then, held in stopped position by a connection to a relatively low direct current voltage supply means. The motor is disconnected from the alternating current source by the deenergization of relays I03 and I02. Deenergization of relay I02 results in the movement of switch blades I04 and I06 to disconnect the motor from its alternating current source and to connect the motor to the current pulse supplying means, which is preferably a capacitor I10. This capacitor is charged to a relatively high direct current potential when the motor 94 is in operation, it then being connected to the output of the rectifier and filter through conductors I36, I12 and resistor I14 (of about 10,000 ohms). The capacitor may have a value of about 64 mf. and it, as already indicated, supplies a pulse of current quickly and effectively to stop the motor when the circuit has been rebalanced. The motor is maintained in its stopped position by a relatively low direct current, the motor being connected across the conductors I36 and I12 through the resistor IN.

The arrangement of the bridge circuit and variable resistors and the resistance value of the encircuited portion of the resistor I4 are such that when the ofi resistor i4 is switched into the bridge circuit, the circuit becomes balanced only when the scriber 92 is moved to its extreme left position, thereby to provide an indication that the receiver has been turned off. An indication that the telephone line is open, which is particularly desirable in the event that the connection is made through a telephone exchange, is given by the location of the scriber 92 at its extreme right position. In the latter case the motor 95 operates the contact 96 of resistor 22 to an open circuit position.

Additional indications of the on and open circuit conditions are given by lamps I80 and I82, respectively. When the radio is turned on, the lamp I80 is supplied with power, and under open circuit conditions, the lamp I82 is supplied with power.

When the radio is turned on, the lamp I80 is connected to a low voltage secondary winding I85 of transformer I28 through conductors I85, the connection being effected by the closure of switch H83 operable by a relay winding I30. The Winding I92 is energized when the radio is turned on by the closure of a power circuit by a switch I02 controlled by a cam I94 in such manner that the switch is closed except when the radio is in its oiT position. In the off position, the switch is opened by the cam, which is rotated to the off position by the motor 94 under the control of the bridge circuit. Power is supplied to the relay winding I from a suitable source, such as the 110 volt supply lines 52.

The open line condition is indicated by the illumination of lamp I82, which is connected across the power lines I86 by a switch blade I96 controlled by a cam 598 under the open circuit condition. The cam and switch are so constructed and arranged that the switch blade I96 closes an energizing circuit for the lamp when the motor 92 is stopped in its off position.

If desired, the scriber 92 may be so constructed and arranged that it is biased away from the record tape and is moved into contact with the tape whenever the radio receiver is turned on. The scriber may be moved into contact with the tape by a solenoid 226 which is supplied with power when the radio is turned on through a switch 202 closed by the relay winding I90 when the latter is energized. Power is supplied to solenoid 260 from a suitable source, such as the direct current lines 30.

If the solenoid 290 is used, then the scriber is moved out of contact with the tape in the off position. However, the angular position of the scriber still indicates that the radio has been turned off.

The use of the off resistor 74 and the scriber in contact with the tape in the off position, en-

ables variations in telephone circuit resistance to be checked. If the scriber solenoid 00 is used, then in order that the line resistance variation can be checked, there is provided a manually closable switch 294 which, when closed, energizes the relay I independently of the cam controlled switch I92.

In accordance with another feature of the present invention, the apparatus is provided with means for visually indicating the network to which the radio station is connected. This means includes a plurality of network indicating lamps 2I0, in this case live, for indicating five networks and a lamp 2 I 2 for indicating stations other than said five or more network stations. The illumination of the lamps is controlled by a drum type controller indicated as a Whole by reference character 2I4, the angular position of which corresponds to the tuning of the radio receiver, and which is angularly movable by the motor 94. This controller forms an important part of my invention, as it, in effect, produces control impulses in a simple and efiective way, which can be used for energizing lights or performing other desired functions.

The drum controller controls, in the embodiment of the invention illustrated, the supply of power to the lamps. It includes a drum having an outer shell 2H3 of conducting material, upon which is mounted a card 2I8 of insulating material having a series of longitudinally and angularly spaced apart perforations 228 corresponding to the various stations. These perforations have angular lengths corresponding to the calibrated band widths of the stations to which they correspond, as will be described in greater detail shortly in conjunction with Figs 2 to 5, inclusive.

The drum controller includes also a series of brushes 222 for each of the lamps, and a single brush 224 connected to ground (or a common conductor) through conductor 226.

Power is supplied to the network indicating means through a transformer 228 having its primary winding 230 connected to a suitable source of power, such as the conductors 42. The low voltage secondary winding 232 of the transformer is connected to a conductor 234 common to the individual lamps and to a ground connection 236.

The controller 2 Id controlling the energization of the lamps will now be described with particular reference to Figs. 2 to 5, inclusive. It is preferably constructed as a unit with the adjustable resistor 22, which is shown in Figs. 2 and 3 as being supported by a vertical plate 240 which, together with a somewhat smaller plate 242, supports the controller. The supports 240 and 242 are mounted upon a base plate 244.

The controller is coupled to the motor 94 through a motor driven shaft 246. The shaft 2% is drivingly connected to a combined drum and potentiometer driving shaft 248 through a coupling sleeve 25!] and a coupling 252.

The outer shell 2I6 of the drum controller is preferably made of suitable conducting material such as brass tubing. The shell is not a complete tube, but rather is made with an arcuate extent somewhat greater than so that the perforated card 2i8 may be readily and detachably secured to it, and because only a 180 portion of the potentiometer 22 is actually used. This portion of resistor 22 is preferably from 0 to about 6,000 ohms, corresponding to the used portion ofthe resistor 20. The shell is suitably secured, as by soldering, to an inner support 254 which is attached to the shaft 248.

The card 2 I 8 is made of some suitable insulating material such as fiber paper or plastic. It is detachably secured to the drum shell H6 in such manner that it may be readily attached or detached. This is of importance, because the perforations 220 in the card must be calibrated with the radio receiver properly to indicate the station and the network with which the station is afliliated. One end 256 of the card is, referring now particularly to Fig. 4, bent around one end of the drum shell and secured to the inside of the shell by a pair of screws 258, only one of which is illustrated in Fig. 4. The other end 269 is bent around the opposite end of and attached to the inside of the shell by resilient means holding the card tightly against the outer surface of the shell. The resilient means includes a pair of springs 252 located near opposite axial ends of the shelland secured to the inside of the shell by small screws 264. The opposite ends of the springs are detachably attached to the end 260 of the card by a. card holder bar 266, the bar being provided with apertures 268 near its opposite ends, enabling the bar easily to be hooked to the springs. The bar is secured to the card by a pair of spaced apart screws 2'10. The bar is guided and held against undesired displacement by a slot 212 in and located near the outer surface of the shell holding member 254.

The brushes 222 and 224 are mounted upon a brush holder indicated generally by reference character 214, movably supported above the shell in order that the brushes may be moved away from the shell as a unit when it is desired to have access to the drum for the purpose of changing cards or the like.

The brush holder 214 is movably supported on a supporting shaft 216 secured at its opposite ends to the supporting plates 24!) and to an extension supporting plate 2 8 secured to the upper end of supporting plate 242.

The brushes are detachably secured to the brush holder by the two detachable parts 280 and 282 of the holder, between which the brushes 222 and 224 are securely held. Brush holder part 280 is movably mounted on the supporting shaft 216 and brush holder part 282 is secured to part 280 by a plurality of screws 284.

The brushes 222 comprise relatively long contact arms 222A made of suitable material, such as Phosphor bronze spring wire, and brush wires 222B secured to the ends of the contact arms and resiliently bearing against the card 218 or the shell 216, as the case may be.

The contact arms and brushes are biased and held against the card and shell by suitable means, such as a snap sprin 286, having one end secured to the brush holder and having its other end bent and provided with a semi-circular bend 288 adapted to fit about a stop pin 29%), thereby to hold the brush assembly in position. The pressure with which the brushes are held against the card and shell by spring 286 is adjusted by a screw 292 which adjusts: the position of the snap spring 226 relative to the brush holder.

The longitudinal position of the brushes is adjustable by the desired location of a pair of spacer collars 294 at opposite ends of the brush holder, and which are detachably secured to the supporting shaft 216.

In the description of the operation of the apparatus, it will be assumed that the radio receiver has been in operation. and that the recording and indicating apparatus has been stopped in a, position corresponding to the station to which the receiver is tuned and that the visual indicating means shows the network afiiliation of the station. At this time the various switches and circuits are in the conditions illustrated in Fig. 1. The plug 46 is connected to a suitable source of alternating current voltage; the test switch I42 is closed as are the motor switch [68 and the power switch 44. The motor 94 is held stopped by the direct current flow through the motor winding, the flow occurring through switch blades I04 and H16 in their illustrated positions. The motor 65] associated with the radio receiver is deenergized, as is the relay 80. Resistor 82 is therefore short circuited by the switch 86 so that the resistor 20 is connected to the bridge circuit through the switch blade 66. Indicator 92 is in a position corresponding to the station tuned in and one of the lamps 2 I G is illuminated.

Assuming now that the user of the radio tunes in another station, then the motor 50 and the relay 8B are energized. The former operates the tuning condenser 19 of the electronic control device and the movable contact 62 to vary resistor 20. The relay opens its switch 88 thereby inserting resistor 82 into the bridge circuit in series with resistor 29. Thus even though the tuning means be operated but a slight distance, the bridge is unbalanced to a considerable extent insuring efiective operation of the apparatus at the central recording station. The unbalance voltage of the bridge is applied to the grids of the vacuum tubes H6 and H8 with the result that current flows through the winding H2 of relay I08. The movable switch blade Ilfi of the relay closes a circuit to energize the winding of relay I92 and the latter operates switch blades 34 and 105 to disconnect the motor from the direct current source and to connect it to the source of alternating current, thereby causing the motor to rotate. The motor therefore operates to move the scriber 92, to adjust resistor 22 and to move the visual indicator controller 2 l 4.

The motor 68 continues to adjust resistor 29 until the condenser 15 has been moved to a position corresponding to the station tuned in, at which time the motor as is deenergized and stopped. The relay 80 is simultaneously deenergizecl. When the motor stops, the resistor 2e has been varied to a value corresponding to or indicative to a radio station to which the receiver is tuned, and it alone remains in the bridge circuit because the resistor 82 is short circuited upon return of switch blade 85 to its indicated position. The motor 94 continues now to operate until resistor 22 has been adjusted to a value balancing the resistor 28. When thus adjusted, the bridge output returns to Zero and the relay I08 is deenergized. The latter effects the deenergization of relay 102, which disconnects the motor from the alternating current source and connects it to the pulseproducing condenser Hi and to the direct current voltage source through resistor ll, thereby quickly to stop the motor and hold it stopped. When the motor stops, the scriber 82 also stops and in a position corresponding to the radio station to which the receiver is tuned.

When the motor rotates, it also rotates the drum 2 it of the visual indicating means and the drum is. stopped. at an angular position corresponding to the station tuned in. The network indicating lamp 2H] corresponding to the station is illuminated through a circuit including the lamp, the corresponding brush 222, perforation 220 and the drum shell 21S and brush 224. The lamp indicates the network affiliation of the station tuned in as the perforation is aligned with the brush connected to the lamp indicating the network. Non-network stations are indicated by the illumination of lamp 2 I2.

The controller drum and perforated card provide accurate indication of stations received close together on the frequency band because they usually are on difierent networks so that the perforations are axially displaced.

Only about one-half of the controller drum and resistors 28 and 22 are used because the stations tuned in on the receiver are recorded only when the scriber 92 is moved in one directionthereby to avoid back lash. For the same reason, the motor 60 of the electronic control associated with receiver, which has a scriber associated with it (not shown) is only stopped for one direction of variation of condenser Hi.

When the tuning of the radio receiver is again varied, the operation is repeated as heretofore described, with the result that the scriber 92 and drum controller 21 iare again operated to new positions corresponding to the station tuned in and network affiliation of the station. A continuous and accurate indication and record are thus made of the stations to which the receiver is tuned and a visual indication is provided of the network.

When the radio receiver is turned oi, the relay till is deenergized (with a brief time delay if the power source includes a rectifier tube having an indirectly heated cathode) and its switch E35 connects the off resistor H3 in the bridge circuit. The bridge circuit is thus unbalanced (and when the time delay type operation occurs, the bridg is unbalanced by operation of the motor for a brief interval) and the motor 94 again energized to adjust resistor 22 until it balances the bridge for the effectiv value of resistor M. in the bridge circuit. As heretofore indicated, this balance occurs when the scriber s2 is at the extreme left of the tape H38. In the off position, the light EBB is extinguished to give a visual indication. The light is extinguished by the opening of switch Hi2 by cam I94, and the subsequent opening of switch 1% upon deenergization of relay Winding I95. At the same time solenoid 2% is deenergized and the scriber lifted from the tape this providing a record of the oil position.

When the receiver is turned on, the relay is energized to disconnect resistor Hi from the bridge circuit and to connect resistor 28 to it. This unbalances the bridge circuit, as does the connection of resistor 82 to the bridge circuit by relay 8%], which is energized along with motor 80 to hunt for the station tuned in by the receiver. The motor 94 is again energizedbecause of the unbalance of the bridge circuit and it operates to adjust resistor 22, to move scriber 92 to indicate and record the tuning of the radio receiver to move the drum control visually to indicate the network.

In the event the telephone line is opened, for example inadvertently at a telephone exchange through which the line extends, the scriber 92 is operated to its Xtreme right position to indicate the open circuit condition. When the telephone line is opened, an infinite resistance is placed in one leg of the bridge with the result that the bridge is unbalanced and the motor as is energized to adjust resistor 22 until it is in, an open 12 circuit position, whereat the bridge is again balanced and the motor 94 stopped.

An indication of short wave reception is also provided. When the receiver is turned to short wave reception, the motor 60 operates continuously to vary the resistor 29. As a result the bridge circuit is continuously unbalanced and motor 94 continuously energized to oscillate the scriber 92 back and forth across the tape.

In order to ascertain if there has been a change in line resistance when the radio receiver is in its oiT position, the switch 284 may be closed so that the scriber will make a record. If the record is not at the normal oil position, an indication of resistance variation is given and this may be be compensated for by adjustment of line balancer resistor 23.

While but a single embodiment of the invention has been described in detail, it should be understood that these details are not intended to be limitative of the invention except insofar as set forth in the accompanying claims. Insofar as modifications of the invention are concerned, it should perhaps be noted that the resistor 23 may be varied by means other than that described. For instance, the variation could be eiIected by mechanically coupling the movable contact 52 directly to the tuning control of the receiver. Other arrangements and types of impedance means may also be used.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. Apparatus for indicating at a central station the tuning of a radio receiver located at a point remote therefrom, including in combination, a movable member at the central station, power means operatively connected to said movable member for moving said member, and means including a circuit extending from the central station to the receiver and receiver tuning condition means operable in response to the tuning of the receiver for controlling the operation or" said power means over said circuit to move said movable member into difierent positions corresponding to the tuning of the receiver, and circuit control means angularly movable by. said member and including a perforated card having perforations of an angular extent corresponding to the band width of the stations tuned in by the receiver.

2. Apparatus for indicating at a central station the tuning of a radio receiver located at a point remote therefrom, including in combination, an angularly movable member at the central station, power means operatively connected to said movable member for rotating said member, and means including a circuit extending from the central station to the receiver and receiver tuning condition means operable in response to the tuning of the receiver for controlling the operation of said power means over said circuit to rotate said movable member into different angular positions corresponding to the tuning oi the receiver, and circuit control means angularly movable by said member and including a drum and a card having angularly and axially spaced apart perforations of an angular extent corresponding to the band width of the stations tuned in by the receiver.

J AMES G. BLACK.

' ere c s on clicw ng p REFERENCES CITED Number The following references are of record in the 1,912,233 file of this patent: UNITED STATES PATENTS 0 2,229,100 Number Name Date 2,439,201 502,399 Haskins Aug. 1, 1893 2,438,207 1,356,804 Brewer Oct. 26, 1920 1,367,583 Bobroff Feb. 3, 1921 1,693,892 Fuchs Dec. 4, 1928 10 Number 1,800,019 Hewett Apr. '7, 1931 11,881

Name Date Delsonno May 30, 1933 Johnson Sept. 26, 1933 Beattie June 4, 1935 Lapsley Jan. 2, 1941 Clark, Jr Apr. 6, 1948 Lea Nov. 15, 1949 FOREIGN PATENTS Country Date Great Britain of 1899 

